Protective Efficacy of Rhomboid-Like Protein 3 as a Candidate Antigen Against Eimeria maxima in Chickens

Abstract

Avian coccidiosis brings tremendous economic loss to the poultry industry worldwide. The third generation vaccine, including subunit and DNA vaccines, exhibited promising developmental prospects. In a previous study, we found rhomboid-like protein 3 of Eimeria maxima (EmROM3) was involved in infections by Eimeria species. However, the protective efficacy of EmROM3 against Eimeria maxima (E. maxima) remains unknown. In this study, chickens were intramuscularly immunized with the recombinant protein EmROM3 (rEmROM3) or pVAX1-EmROM3 to determine the EmROM3-induced immune response. The induced humoral immune response was determined by measuring serum IgG antibody levels in immunized chickens. The induced cellular immune response was detected by measuring the transcription level of immune related cytokines and the proportion of T cell subsets of the immunized chickens. Finally, the protective efficacy of the EmROM3 vaccine against E. maxima was evaluated by immunization-challenge trials. Results revealed that the purified rEmROM3 reacted with chicken anti-E. maxima serum. The recombinant plasmid of pVAX1-EmROM3 was transcribed and translated in the injected muscle from the vaccinated chickens. In experimental groups, the IgG titers, proportions of CD4+ and CD8+ T cells, and transcription level of splenic cytokines were significantly increased compared with the control groups. The immunization-challenge trial revealed that immunization with rEmROM3 or pVAX1-EmROM3 led to restored weight gain, alleviated enteric lesion, decreased oocyst output as well as the higher anticoccidial index (ACI), indicating partial protection against E. maxima. These results indicate that EmROM3 is an effective candidate antigen for developing novel vaccines against infection by E. maxima.

A multiepitope vaccine encoding four Eimeria epitopes with PLGA nanospheres: a novel vaccine candidate against coccidiosis in laying chickens

“…Our data supported the idea that NSLC protein as well as vaccines could generate an immune response, indicating that NSLC protein and vaccines possessed satisfactory immunogenicity. Similar to our results, immunity could be induced by the recombinant pET-32a-EmROM3 protein in chickens [52]. Furthermore, with the increased titres of IgY in immunized animals, our results also suggested that a booster immunity could be elicited by NSLC protein and vaccines.…”

Identification and Protective Efficacy of Eimeria tenella Rhoptry Kinase Family Protein 17

“…Serum levels of anti-EtROP17 antibodies were examined by ELISA as described elsewhere [ 8 ]. Briefly, the 96-well plate was coated with purified rEtROP17 and incubated overnight at 4 °C.…”

“…Serum levels of anti-EtROP17 antibodies were examined by ELISA as described elsewhere [8]. Briefly, the 96-well plate was coated with purified rEtROP17 and incubated overnight at 4 • C. Following washing thrice with PBST, the plate was blocked with 5% skimmed milk in PBST.…”

“…Meanwhile, live anticoccidial vaccines are used commercially for the control of avian coccidiosis [6]. However, the use of live anticoccidial vaccines or anti-parasitic drugs has disadvantages, such as the occurrence of drug resistance, complex production processes, and potential pathogenicity [7,8]. Hence, the Animals 2022, 12, 556 2 of 9 development of novel control measures such as subunit vaccines has attracted widespread attention [9].…”

An Eimeria maxima Antigen: Its Functions on Stimulating Th1 Cytokines and Protective Efficacy Against Coccidiosis

“…Eukaryotic expression vector pVAX1 was purchased from Invitrogen (Carlsbad, California). Prokaryotic expression vector pET-28a, uninfected chicken serum, and chicken antiserum against E. maxima were preserved in our lab ( 10 , 11 ). Sporulated oocysts of E. maxima were stored in 2.5% potassium dichromate at 4°C.…”